Future pandemics could be more lethal than the current Covid crisis, one of the creators of the Oxford-AstraZeneca vaccine has warned.

Prof Dame Sarah Gilbert, delivering the 44th Richard Dimbleby Lecture, said there needed to be more funding for pandemic preparedness to prevent the advances made from being lost.

She also warned vaccines could be less effective against the Omicron variant.

Dame Sarah added that people should be cautious until more was known about it.

She said: "This will not be the last time a virus threatens our lives and our livelihoods. The truth is, the next one could be worse. It could be more contagious, or more lethal, or both.

"We cannot allow a situation where we have gone through all we have gone through, and then find that the enormous economic losses we have sustained mean that there is still no funding for pandemic preparedness," she added.

"But there are additional changes that may mean antibodies induced by the vaccines, or by infection with other variants, may be less effective at preventing infection with Omicron.

"Until we know more, we should be cautious, and take steps to slow down the spread of this new variant."

However, Dame Sarah said reduced protection against infection and mild disease would not necessarily mean reduced protection against severe illness and death.

She also called for the rapid progress seen in delivering vaccines and medicines during the pandemic to become the norm.

There was no reason why a universal flu jab could not be developed in order to wipe out the threat from influenza, she said.

From 04:00 GMT on Tuesday travellers aged 12 and over will be required to show proof of a negative PCR or lateral flow test taken no earlier than 48 hours before departure.

And Nigeria has now been added to the travel red list after a growing number of Omicron cases were linked to the country.

But a scientist advising the government said the travel rule changes were "a case of shutting the stable door after the horse has bolted".

Prof Mark Woolhouse said the new rules had come too late to make a "material difference" to a potential wave of the Omicron variant in the UK.

Prof Woolhouse, a member of the government's Scientific Pandemic Influenza Group on Modelling (Spi-M), told the BBC's Andrew Marr show that Omicron was "spreading pretty rapidly" in the UK, and if current trends here and in South Africa continued in the coming weeks and months, it could replace Delta as the world's dominant strain.

The UK recorded 86 new cases of the Omicron variant on Sunday, taking the total so far to 246. In total, 43,992 cases and 54 deaths within 28 days of a positive coronavirus test were recorded on Sunday.

Dame Sarah - who was recognised with a damehood in the Queen's Birthday Honours earlier this year - began designing a coronavirus vaccine in early 2020 when Covid first emerged in China.

The Oxford-AstraZeneca jab is now the most widely used around the world, with doses sent to more than 170 countries.

The lecture, named after the late broadcaster, Richard Dimbleby, features influential speakers from academia, arts and business and the Royal Family.